Case Study - Agricultural Slurry Spill
Background
A section of concrete wall forming a slurry store failed leading to a loss of approximately 500,000 litres of cattle slurry. The store was located at the top of a hill and the slurry flowed downhill and into a stream in the valley bottom and flowed a distance of 1.2 km to the confluence with a larger river. The slurry covered an area of farmland estimated to be 10,000 square metres.
Oracle provided initial advice to the farmer including recommending the deployment of straw bales in the watercourse to prevent further migration of slurry.
Mitigation & Remediation
Oracle dammed the impacted stream upstream of the point the slurry entered and setup and over-pumping system over a distance of 400 m to prevent water flowing through the worst affected area.
A temporary lagoon was excavated by a farm contractor to allow the storage of slurry recovered. The farm contractor began removal of slurry from the worst affected area of stream using an excavator and Oracle installed further downstream dams and flushed and recovered slurry from the streambed and banks over a length of 400 m.
A further 800 m of stream was cleared of slurry using a combination of high pressure washing and mechanical excavation. All recovered slurry was returned to the farm for spreading with no waste generated for disposal.
Outcome
The stream was restored and water quality monitoring and sampling were undertaken to confirm no further impact to the stream. The works were undertaken in consultation with NRW and they confirmed the works were successful, and thanks to the swift response, no fish were reported to have died as a result of the slurry spill incident.